Easy opening device for a rectangular container end

ABSTRACT

An easy opening rectangular container wall which has a line of weakness around its periphery defining a removable portion in the container wall and which has a tab attached to the removable portion in one corner, as by means of an integral rivet, and a downward embossment in the removable portion including a wing section spread outwardly from adjacent the attachment and a narrow tail section joined to the wing section.

United States Patent Schrecker [451 Apr. 4, 1972 I 54] EASY OPENING DEVICE FOR A RECTANGULAR CONTAINER END [72] Inventor: Howard Dale Schreeker, Hyde Park, Pa.

[73] Assignee: Aluminum Company of America, Pittsburg, Pa.

[22] Filed: Aug. 31, I970 [2]] Appl. No.: 68,318

[52] US. Cl ..220/54 [51] Int. Cl ..B65d 17/24 [58] Field of Search ..220/54, 48, 53, 27; 222/541; 215/46 A [56] References Cited UNITED STATES PATENTS Stec ..220/54 3,478,918 11/1969 Zundeh ......220/$4 3,591,037 7/1971 Schrecker..

Primary Examiner-Ge0rge T. Hall Attorney-David W. Brownlee [57] I ABSTRACT An easy opening rectangular container wall which has a line of weakness around its periphery defining a removable portion in the container wall and which has a tab attached to the removable portion in one corner, as by means of an integral rivet, and a downward embossment in the removable portion including a wing section spread outwardly from adjacent the attachment and a narrow tail section joined to the wing section.

5 Claims, 3 Drawing Figures PATENTEDAPR 4 1972 INVENTOR Howard Dole Schrecker ATTORNEY BACKGROUND OF THE INVENTION Containers having walls made of deformable material have been provided with large removable portions of the full pullout panel type which are defined by lines of weakness around the outer periphery thereof and having tabs affixed to the removable portions for rupture of the lines of weakness as shown, for example, in US. Pat. Nos. 3,430,802 and 3,478,918. Removal of such full pull-out panel portions is typically effected by lifting the tab to initiate rupture of the line of weakness adjacent the attachment of the tab to the removable panel portion and then pulling the tab to rupture the remainder of the line of weakness around the removable portion. It has been found that in pulling out such large removable portions, the pulling force exerted on the panel by the tab sometimes deforms the panel and causes it to bend and curl adjacent the tab. This makes it difficult to rupture the line of weakness and remove the panel. To help ease this problem, the two above identified patent disclosures speak of embossed beads in the removable panel portion of a circular container end provided to prevent doming but permit curling of the removable panel portion. In a rectangular container, however, such embossed beads do not always provide the desired ease of opening. It is known that in a removable panel portion having a rectangular configuration it is desirable to attach the tab to the removable portion in one corner so that lifting the tab will effect initial rupture of only a short are of the score line. This eases the initial rupture of the score and facilitates removal of the panel from the container. However, when the tab is attached to the corner ofa rectangular removable panel portion it is sometimes difficult to effect rupture of the score around the nearest adjacent corner of the removable portion. Accordingly, an easy opening device for a rectangular container end is desired which can be removed with a minimum of effort.

SUMMARY OF THE INVENTION This invention provides an easy opening device for a rectangular container wall having a score around the periphery of the container wall defining a rectangular removable portion and a tab attached to the removable portion in one corner thereof, and further having a downward embossment in the removable panel portion which includes a wing section which diverges outwardly from the attachment of the tab to the removable panel portion and a narrower tail section joined to the wing section and extending approximately to a line bisecting the nearest adjacent corner of the removable portion.

Accordingly, an object of the invention is to provide means for facilitating the opening of an easy opening device in 'a rectangular container end.

Another object of the invention is to provide a downward embossment in a removable portion of a rectangular container panel which facilitates rupture of the score line around the corner of the panel adjacent the corner in which the tab is attached to the panel.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects and advantages of the invention will be more fully understood and appreciated with reference to the following specification and the drawings appended hereto wherein:

FIG. 1 is a plan view illustrating a container provided with an easy opening device in its end wall in accordance with the invention;

FIG. 2 is an enlarged cross-sectional view of the container taken along line II-II ofFIG. l; and

FIG. 3 is a perspective view illustrating opening of the container of FIGS. 1 and 2.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to the drawings, a preferred embodiment of the invention is illustrated in the form of a rectangularly shaped container 10 having an end wall or panel thereof made of metal, preferably aluminum or aluminum alloy of a relatively thin gauge in the range of 0.007 inch to 0.012 inch. The end wall has a peripheral flange 12 which may be secured to side wall 14 of container 10 by conventional means such as double seaming. A rectangularly shaped full pull-out panel portion 16 defined by a score line 18 or other line of weakness is provided in the container wall for gaining access the contents of the container. Score line 18 is formed closely adjacent peripheral flange 12 so that a major portion of the end wall can be removed to facilitate access to, and removal of, the contents of the container. An anti-fracture score line 20 which is shallower, or has a thicker residual, than score 18 may also be provided in the end wall inwardly of and adjacent to score line 18 as shown. Preferably, the side wall 14 of the container has a shoulder 22 around the periphery of the container underlying score line 18 to shield the edge of the score after the removal of the panel portion. This shielding of the ruptured edge of the score helps to reduce or eliminate accidental injury to the user which could otherwise result from contact of the user's hand with the sharp score edge.

A pull tab 24 is disposed over the full pull-out panel portion 16 and affixed to the panel near its edge by conventional means such as an integral rivet 26. With a square or rectangular container, as illustrated, the starting end of the removable portion 16 is located in a corner thereof to facilitate opening of the container. To initiate opening of removable portion 16, there need only be initial rupture of a short length of the score line 18 at such corner, and severance of the score line can be progressive thereafter. Since only a short are of the score line is ruptured when the tab is lifted, the force which is required to initiate this rupture is relatively small. For example, this initial rupture force or pop force" for an end wall made of 0.009 inch aluminum alloy will average approximately three pounds for a container wall as shown in the FIGS.

Tab 24 has a nose end 28 overlying the removable panel portion 16 adjacent score line 18 and a handle end 30 in the shape of a ring disposed inwardly of score line 18 and overlying panel portion 16. Tab 24 is preferably formed of sheet metal such as aluminum or an alloy thereof and has a curled bead around the ring and along the sides of the tab. The nose end 28 of tab 24 may be recessed around the attachment portion to provide a wall which is substantially flush with the panel portion 16 of container 10, and the tab may include reinforcement ribs 32 adjacent such recessed area. The nose 28 of the tab 24 may also be provided with upwardly turned lips along the edge thereof to reinforce the nose and provide a concentration of force at its end.

It is a feature of the invention that removable panel portion 16 has a downward embossment therein comprised of an wing section 34 which spreads or diverges outward in the panel from the attachment rivet 26, and an embossed tail section 36 which is narrower than the wing section and joined to that section. The tail section 36 extends along a line bisecting the tabattachment corner of the panel portion 16 approximately to a line bisecting the corner of the container wall closest to the corner in which the attachment rivet is located. The sections 34 and 36 have substantially fiat bottom walls, and the opposite sides of the wing section 34 extend along the cornerforming end and side of the removable portion 16. These embossed sections 34 and 36 form a substantially rigid zone in the removable portion which resists flexing and bending of the removable portion both parallel and transverse to the direction in which the tab is pulled. The downwardly embossed tail section also facilitates insertion of a finger under the tab so that the tab can be easily gripped for lifting it to initiate opening.

In the end closures heretofore known, the embossed beads in the removable panels have been designed to reinforce the panels in one direction only to prevent upward bowing or doming of the section transverse to the direction of tearing while permitting the panel to curl. The ends included no provision for reinforcing the panel parallel to the direction of tearing so that the panel would be substantially rigid and would not curl. It has been discovered that by preventing curling as well as doming of the removable panel, rupture of the score can be made even easier, particularly in rectangular con tainers. It has also been found that for a rectangular end closure with a rectangular removable portion, the rigid zone should extend approximately to a line bisecting the corner of the panel nearest to the attachment of the tab to the removable panel so that rupture of the score around such nearest adjacent corner can be easily effected. The removable panel should preferably flex as rupture of the score proceeds around such adjacent corner to facilitate a change of direction in the pulling force. if the rigid zone extended much beyond the line bisecting that corner, the flexing which permits this change of direction of pulling force would be difficult. On the other hand, if the rigid zone ended too far short of the bisecting line, the removable panel would start to flex too soon which would make it difficult to rupture the score into the adjacent corner. With an end closure as shown, the rigid zone acts as a lever which fulcrums at the adjacent corner to aid in rupture of the score around such corner.

The two different widths and depths of embossment as shown in Figs. also facilitate rupture of the score. More reinforcement is required closer to the attachment of the tab, and the deeper and wider embossed section is provided in this area. Less reinforcement is required further from the rivet attachment, and the narrower tail section permits the desirable flexure of the removable panel in the area of the adjacent corner. In a preferred embodiment of the invention the wing embossment 34 is depressed approximately 0.0017 inch and the tail embodiment is depressed approximately 0.008 inch, although shallower embossments can be used. Preferably, however, the wing section should be at least 0.0015 inch deep and the tail section at least 0.006 inch deep to provide adequate reinforcing strength for the intended purpose.

To open a container with an easy opening device of the invention, tab 24 is lifted to depress the removable panel between score 18 and rivet 26 into the container and thereby rupture the score around the short are of the corner of the container. The tab is then pulled to rupture the score along the removable panel outward from the initial point of rupture. Since the panel is substantially rigid, the residual metal in the score is put into almost perfect shear which means the metal ruptures with a minimum of force. The removable panel domes and curls very little, if any, during this rupture of the score 18. If the panel were permitted to bow, the score is put in tension rather than shear. This makes it difficult to rupture the score and may result in pulling the end seam from the container wall. If the panel were permitted to curl, a degree of tension is also produced since the curled edge of the panel is not in line with the score. With a rigid removable panel portion of the invention both curling and doming of the panel are to eliminated which makes it easier t rupture the score than was possible with the prior opening devices. For purposes of comparison, specimen rectangular ends which had parallel beads similar to those shown in LaCroce et al. US. Pat. No. 3,430,802 and rectangular ends which had embossed sections of the invention were opened and the forces required to effect the rupture of the scores were measured. For the ends with parallel beads in them, the pull force averaged 10.0 pounds, whereas for the ends of the invention the average pull force was only 8.6 pounds.

When score 18 has been ruptured to the adjacent corner of panel 16, the panel will then curl around the corner. Since there is no reinforcement in this corner, the direction of tearing is easily shifted. The score is then ruptured along the long sides of the panel 16, and the score along the other short end of the panel is stressed to rupture it and remove panel 16 from the container wall.

It is therefore seen that an easy opening device 15 provided for a rectangular container wall in which a major portion of the wall can be removed very easily. While a specific embodiment of the invention has been selected and illustrated, it will be appreciated by those skilled in the art that various modifications can be made in the device which has been described. For example various tab structures can be employed which would not affect the invention.

What is claimed is:

1. In a rectangular container wall of deformable material having a line of weakness around its periphery defining a rectangular removable portion therein and having a tab attached to the removable portion in one corner thereof, the improvement comprising a downward embossment in the removable portion including an embossed wing section spread outwardly from adjacent the attachment of the tab to the removable portion, and an embossed tail section narrower than the wing section, the tail section being joined to the wing section and extending approximately to a line bisecting the nearest adjacent corner of the removable portion.

2. A container wall combination as set forth in claim 1 in which said embossed tail section is shallower than said embossed wing section.

3. A container wall combination as set forth in claim 1 in which said tail section underlies the lifting end of the pull tab, thereby facilitating gripping of the tab.

4. A container wall combination as set forth in claim 1 in which said wing section is at least 0.015 inch deep and said tail section is shallower than said wing section but is at least 0.006 inch deep.

5. A container wall combination as set forth in claim 1 in which said embossed wing section has a flat bottom wall with opposite sides of the section extending along the corner-forming end and side of the removable portion, and said tail section extends along a line bisecting the tab-attachment corner. 

1. In a rectangular container wall of deformable material having a line of weakness around its periphery defining a rectangular removable portion therein and having a tab attached to the removable portion in one corner thereof, the improvement comprising a downward embossment in the removable portion including an embossed wing section spread outwardly from adjacent the attachment of the tab to the removable portion, and an embossed tail section narrower than the wing section, the tail section being joined to the wing section and extending approximately to a line bisecting the nearest adjacent corner of the removable portion.
 2. A container wall combination as set forth in claim 1 in which said embossed tail section is shallower than said embossed wing section.
 3. A container wall combination as set forth in claim 1 in which said tail section underlies the lifting end of the pull tab, thereby facilitating gripping of the tab.
 4. A container wall combination as set forth in claim 1 in which said wing section is at least 0.015 inch deep and said tail section is shallower than said wing section but is at least 0.006 inch deep.
 5. A container wall combination as set forth in claim 1 in which said embossed wing section has a flat bottom wall with opposite sides of the section extending along the corner-forming end and side of the removable portion, and said tail section extends along a line bisecting the tab-attachment corner. 